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Some high-threat volcanoes are severely understudied: Study

The Cascade Volcanic Arc stretches from Northern California to southern British Columbia and contains more than a dozen volcanoes. The U.S. Geological Survey classifies 11 of them, including Mount Baker and Mount Hood, as ...

A new theory to explain the nature of volcanic fountaining

A multi-institutional team of Earth scientists, meteorologists, geologists and volcanologists has developed a new theory to explain the nature of volcanic fountaining. In their project, reported in the journal Nature Communications, ...

Image: Italy's Mount Etna spews lava

One of the world's most active volcanoes, Mount Etna, erupted on Sunday—spewing lava and clouds of ash high over the Mediterranean island of Sicily. This image, captured on 13 November by the Copernicus Sentinel-2 mission, ...

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A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time. The word volcano is derived from the name of Vulcano island off Sicily. In turn, it was named after Vulcan, the Roman god of fire.

Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.

Volcanoes can be caused by mantle plumes. These so-called hotspots, for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons.

This text uses material from Wikipedia, licensed under CC BY-SA